The present invention relates to a device for a settable plunging unit, and more particularly concerns a torque transmitting axial plunging unit for a vehicle driveline.
One type of axial plunging unit for transmitting torque in a vehicle driveline includes a profiled sleeve with circumferentially distributed, longitudinally extending first ball grooves, a profiled journal with circumferentially distributed, longitudinally extending second ball grooves and balls which are arranged in pairs of first and second ball grooves in k groups of balls. All of the balls arranged in a pair of first and second ball grooves are referred to as a group. When such plunging units are assembled in large volumes, the tolerances of the profiled sleeves and of the profiled journals are compensated for by using different ball sizes. For this purpose, it is necessary to use ball cages with different balls, with the differences referring to different ball diameters. The ball diameters, however, are identical for any one individual ball cage. The suitable ball cages are selected during manual assembly, with the selection criterion being the plunging force of the unit in the ungreased condition. Although the profiled sleeve and the profiled journal can be produced as dimensionally highly accurate components, the cage selection nonetheless is required during assembly. This is because different degrees of distortion during the heat treatment of the profiled sleeve and the profiled journal. Different degrees of distortion result from the tolerances of semi-finished products, tool-related variations and other changes taking place during the production process.
Even though such variations are very slight within individual batches, it can happen that plunging units have to be assembled and tested with several cages until the required plunging force has been achieved. This leads to delays in assembly.
Thus, there exists a need for an improved settable plunging unit.
It is an object of the present invention to provide settable plunging units which can be assembled into well-functioning assemblies which have a standard, ball-containing type of cage.
According to a first solution, at least the number of first ball grooves corresponds to m times the number k of the groups of balls. Also, the longitudinal axes of the first, second, etc. to the mth of the first ball grooves are positioned on different outer pitch circle diameters (PCDa). In addition, the number of second ball grooves can correspond to n times the number k of the groups of balls, and the longitudinal axes of the first, second, etc. to the nth of the second ball grooves are positioned on different inner pitch circle diameters (PCDi).
According to a second solution, at least the number of first ball grooves corresponds to m times the number k of the groups of balls and the first, second, etc. to the mth of the first ball grooves comprise different outer track circle diameters (GLDa). Further, the number of the second ball grooves can correspond to n-times the number k of the groups of balls, and the first, second, etc. to the nth of the second ball grooves can comprise different inner track circle diameters (GLDi).
Herein m represents the number of different types of first ball grooves and n represents the number of different types of second ball grooves, with k being the number of uniformly circumferentially distributed groups of balls.
The present invention makes it possible to introduce the ball cage in m different positions into the profiled sleeve, and in each position, a different play value occurs with a predetermined ball journal. In the above-mentioned further solution, it is additionally possible to introduce the profiled journal in n different positions into the cage, and in this case, too, a different play value is generated relative to the already predetermined configuration of balls and tracks in the profiled sleeve. The total number of different ball play values in the pairs of tracks is calculated by mxc3x97n. Whereas m, due to the relatively large sleeve diameter, depending on the number of groups of balls in the cage, normally ranges between 2 and 3, it can be assumed that n, as a rule, is no greater than 2. In particular, this applies if as high a number as possible, i.e. at least three, but preferably four, groups of balls are used. If this number is reduced to only two groups of balls, n, too, can have a value of 3.
The positions in which the components are associated with one another in the direction of rotation can be indicated by markings applied to the components during the production of the ball grooves. The ball grooves can be designed in such a way that, when the cage is rotated in a certain direction, the plunging force can be changed in a predetermined manner.
The cages are filled with several circumferentially distributed groups of balls arranged in rows. The number of balls in each group and their greatest distance from one another are related to the tilting play between the profiled sleeve and the profiled journal. When changing the plunging force, the tilting play changes slightly at the same time.
Preferred embodiments are illustrated in the drawings and will be described below. Other advantages and features of the invention will become apparent upon reading the following detailed description and appended claims, and upon reference to the accompanying drawings.